As we speculated earlier in the year, this isn't going to be a US remake of the series but a big, international next chapter, with John Barrowman and Eve Myles reprising their roles as Jack and Gwen. That's all they can bring back, as everyone else is dead (Rhys will presumably spend the series at home looking after the baby). Which brings us to the crucial question: given that this is a US co-production, they're presumably going to bring in some American actors. So who might be added to the new Torchwood team?

The obvious first box to tick would be James Marsters. He's the ultimate go-to guy for US cult telly, and already exists in the Torch-verse, having played Jack's old (ahem) sparring partner Captain John. And as Russell T Davies made no secret of Joss Whedon's godlike influence over the show, and I'd be amazed if there aren't shadowy meetings going on as we speak to have him guest-write an episode, some of Whedon's extended repertory company would be a shoo-in. Eliza Dushku as a new female lead or femme fatale? Neil Patrick Harris as a new love interest for Jack? Nathan Fillion as Jack's new nemesis? Seth Green as the team goof?

Certainly, getting established sci-fi favourites in would seem an obvious way of bumping up the (already significant) interest across the ocean. Katee Sackhoff has proved her chops as an action heroine across the board, and would bring in the Battlestar Galactica audience. Perhaps her co-star in the doomed Bionic Woman, Michelle Ryan, could give Stateside success another go? Likewise, Dominic Monaghan is a Brit with success in the US. And many of his former co-stars from Lost and FlashForward, along with most of the Heroes cast, are now going to be looking for work.

Meanwhile, there were plenty of secondary characters from Torchwood still floating around at the end of Children Of Earth. There was talk on this blog of Liz May Brice's Johnson and Cush Jumbo's Lois Habiba proving themselves as worthy additions to the Torchwood team. And let's not forget, Captain Jack was last seen in Doctor Who at the end of The End of Time, getting his flirt on with Russell Tovey's Alonso Frame, surely setting up something. Come to that, Martha and Mickey are still running round somewhere fighting Sontarans.

Or maybe we should be thinking further outside the box here. Kristen Chenoweth (or any of the other Glee cast) for a Buffy-inspired musical episode? Established Brit megastar Hugh Laurie? Barrowman's old mate from Desperate Housewives, Eva Longoria? Chace Crawford from Gossip Girl? Kiefer Sutherland?!

So … with one eye on the plausible, and the other on your fantasy line-up, who would you like to see in the new transatlantic Torchwood team? There can only be one certainty, the BringBackIanto hashtags are sure to be springing up as we speak.